This invention relates to a method for heating and evaporation treatment of a waste solution produced by accompaniment with developing processing of a light-sensitive photographic material by an automatic processing machine for photography (in the present specification, abbreviated as photographic processing waste solution or waste solution) and a device therefor, particularly to a method adequate for inhibiting effectively bad odor and a device therefor.
In recent years, as the photographic processing by means of the so-called non-water washing automatic processing machine, which performs substantially no water washing by reduction of replenished amount or stabilizing processing substituting for washing, has been widely spread, the amount of waste solution has been reduced to a great extent.
However, also by such photographic processing of such low replenishing or non-water washing system, even in a relatively small scale processing, for example, in processing of X-ray light-sensitive material, about 10 l of waste solution are produced, and about 30 l per day in processing of light-sensitive materials for printing plates and about 50 l per day in processing of color light-sensitive materials, and treatment of such waste solution causes a problem.
The present inventors have found that the evaporation method is excellent for efficient treatment of a photographic processing waste solution of high concentration (e.g. BOD: 20,000 to 30,000 ppm, NH.sub.4.sup.+ : about 20,000 to 40,000 ppm) with a small amount and have made various proposals (see Japanese patent application Nos. 259006/1985 (Publication No. 118346/1987); No. 259008/1985 (Publication No. 118347/1987); No. 259009/1985 (Publication No. 118348/1987); No. 132098/1986 (Publication No. 287244/1987); No. 165099/1986 (Publication No. 19655/1988); and No. 165100/1986 (Publication No. 19656/1988).
However, in the heating and evaporation method, there is a problem that bad odor based on sulfurous acid gas, hydrogen sulfide gas, sulfur cas, ammonia gas, amine gas, etc. is generated from the evaporated gas or the distillate, etc., and no completed process could be established unless this problem was solved.
In the prior art, as the countermeasure against such bad odor, Japanese Unexamined Utility Model Publication No. 70841/1985 proposes a method in which an adsorption treatment portion is provided at the discharging pipe portion.
However, this method is based on the same technical thought as in the discharging gas treatment known in the art in that the bad odor gas discharged is treated by adsorption at the terminal end (immediately before discharged out of the system, hereinafter the same), and it was not adequate as the gas treatment equipment to be added to the small scale waste solution treatment equipment as in the present invention.
More specifically, bad odor gas may be generally (although different depending on the components) considered to be treated by an equipment of adsorption, etc. if the problem of condensation can be solved, but the bad odor gas concentration in the waste gas obtained by evaporation of the photographic waste solution is extremely high, and when the odor gas of such high concentration is attempted to be treated by adsorption, the adsorbent will be soon saturated, whereby running cost may become enormous and also the exchange work of the adsorption is required to be performed frequently, thus being disadvantageously cumbersome. Further, if the exchange work is attempted to be made less frequent, the size of the adsorption tower is required to be made greater, whereby increase of the installation cost will be disadvantageously brought about.
On the other hand, the techniques of irradiating the evaporated gas with UV-ray or applying ozone oxidation treatment on the distillate have been known, but these techniques involve the drawbacks of high installation cost and cumbersome maintenance.